That's just selvage from the bottom of the sheet. Here's what the full sheet looks like.

It doesn't appear to me to be a double perf. There were two perf varieties, line (Michel 800A) and comb (800B). This appears to be an 800A. The perf quality wasn't always the best on these (see the bottom perfs), and the weak perforation causes the fuzziness around the perfs on the separated edges.